Tooth pulpitis is a prevalent oral disorder. Understanding the underlying mechanisms of pulpitis and developing effective treatment strategies hold great significance. Ferroptosis has recently emerged as a new form of cell death, but the role of ferroptosis in pulpitis remains largely unknown. In our study, single-cell RNA sequencing (scRNA-seq) was used to identify cellular heterogeneity between 3 pulpitis tissue and 3 healthy pulp tissue, and explored ferroptosis occurrence in pulpitis tissue and inflamed dental pulp cells (DPCs). In scRNA-seq, 40 231 cells (Pulpitis: 17 814; Healthy pulp: 22 417) were captured, and visualized into 12 distinct cell clusters. Differentially expressed ferroptosis-related genes (DE-FRGs) were almost presented in each cluster in pulpitis vs healthy pulp. ROS and Fe²⁺ levels significantly rose, and immunohistochemistry showed low expression of GPX4 and high expression of PTGS2 in pulpitis. In LPS-stimulated DPCs, thymosin α1 increased the expression of GPX4 and FTL, and decreased expression of TNF-α, IL-1β, IL-6, and Fe²⁺ levels. In rat pulpitis models, both prothymosin α (PTMA, precursor of thymosin α1) gelatin sponge placed at the hole of pulp (LPS-P(gs)) and PTMA injection in pulp (LPS-P(i)) significantly reduced infiltration of inflammatory cells and expression of PTGS2, and increased the expression of GPX4. In RNA sequencing, the expression of DE-FRGs were reversed when thymosin α1 were added in LPS-stimulated DPCs. Collectively, single-cell atlas reveals cellular heterogeneity between pulpitis and healthy pulp, and ferroptosis occurrence in pulpitis. Thymosin α1 may reduce ferroptosis in DPCs to alleviate pulpitis and thus potentially has the ability to treat pulpitis.
Ferroptosis/drug effects* ; Dental Pulp/drug effects* ; Animals ; Pulpitis/pathology* ; Rats ; Thymalfasin/pharmacology* ; Humans ; Male ; Thymosin/pharmacology* ; Disease Models, Animal ; Rats, Sprague-Dawley

Objective:To investigate the application effect of population/patient, intervention/exposure, comparison/control, and outcome (PICO) principles based on evidence-based medicine in case reports of residents in operative dentistry and endodontics.Methods:A total of 56 residents in Department of Conservative Dentistry and Endodontics in Hospital of Stomatology, Sun Yat-sen University, were selected and randomly divided into experimental group and control group, with 28 residents in each group. The residents in the experimental group were guided by the teachers to apply PICO principles in preparing case reports, and those in the control group were guided by the teachers to prepare traditional case reports. The two groups were compared in terms of the language expression of case reports, the completeness of case records, the rationality and advancement of the diagnosis and treatment regimen, and the logicality and scientificity of discussion, and a questionnaire survey was performed for both groups. SPSS 24.0 software was used to perform the descriptive statistical analysis, the t-test, and the chi-square test. Results:The experimental group had a significantly higher mean score of case report than the control group in department examination [(89.25±3.24) vs. (86.32±3.55), t=3.23, P=0.002], especially the score of the logicality and scientificity of discussion [(27.25±0.16) vs. (23.78±0.36), t=8.77, P<0.001]. The questionnaire survey showed that the experimental group had a significant increase in the frequency of participating in case reports ( P=0.035). Conclusions:The application of PICO principles can enhance the overall quality of case reports by residents and improve their enthusiasm in participating in case reports in department of operative dentistry and endodontics.

Root canal obturation is conducted by using filling materials to tightly seal the root canal system after the procedure of preparation in order to control infection and promote periapical healing. The quality of root canal obturation is one of the essential factors affecting the prognosis of root canal treatment. Qualified root canal filling is defined as a homogeneous radiographic apical filling within the cemento-dentine junction with neither overfilling nor underfilling. This review elucidates the long-term outcome of root canal overfilling and its causes, the influence of apical overfilling on adjacent structures and the prevention and management of overfilling, so as to help the clinicians achieving a better outcome of root canal treatment and obtaining an optimal long-term prognosis.

OBJECTIVETo investigate the differential expression profile and bioinformatic analysis of microRNA (miRNA) in human dental pulp cells (DPC) during endothelial differentiation.

METHODSDPC were cultured in endothelial induction medium (50 µg/L vascular endothelial growth factor, 10 µg/L basic fibroblast growth factor and 2% fetal calf serum) for 7 days. Meanwhile non-induced DPC were used as control.Quantitative real-time PCR (qRT-PCR) was applied to detect vascular endothelial marker genes [CD31, von Willebrand factor (vWF) and vascular endothelial-cadherin (VE-cadherin)] and in vitro tube formation on matrigel was used to analyze the angiogenic ability of differentiated cells. And then miRNA expression profiles of DPC were examined using miRNA microarray and then the differentially expressed miRNA were validated by qRT-PCR. Furthermore, bioinformatic analysis was employed to predict the target genes of miRNA and to analyze the possible biological functions and signaling pathways that were involved in DPC after induction.

RESULTSThe relative mRNA level of CD31, vWF and VE-cadherin in the control group were (3.48 ± 0.22) ×10(-4), (3.13 ± 0.31) ×10(-4) and (39.60 ± 2.36) ×10(-4), and (19.57 ± 2.20) ×10(-4), (48.13 ± 0.54) ×10(-4) and (228.00 ± 8.89) ×10(-4) in the induced group. The expressions of CD31, vWF and VE-cadherin were increased significantly in endothelial induced DPC compared to the control group (P < 0.05). For in vitro tube formation assay, tubular structures were formed on the matrigel by differentiated DPC. A total of 47 miRNA were differentially expressed, in which 15 miRNA were up-regulated and 32 miRNAs down-regulated in differentiated DPC compared with the control. Of these, 4 miRNA were confirmed by qRT-PCR. The target genes of differential miRNA were predicted to associate with several biological functions, such as the regulation of transcription, cell motion, blood vessel morphogenesis, angiogenesis and cytoskeletal protein, and signaling pathways including the mitogen-activated protein kinase (MAPK) and the Wnt signaling pathway.

CONCLUSIONSThe differential miRNA expression identified in this study may be involved in governing DPC endothelial differentiation, thus contributing to the future research on regulatory mechanisms in dental pulp angiogenesis.

Antigens, CD ; Cadherins ; Cell Differentiation ; Collagen ; Computational Biology ; Dental Pulp ; metabolism ; Drug Combinations ; Fibroblast Growth Factor 2 ; Humans ; Laminin ; MicroRNAs ; Platelet Endothelial Cell Adhesion Molecule-1 ; biosynthesis ; Proteoglycans ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Signal Transduction ; Vascular Endothelial Growth Factor A ; Wnt Signaling Pathway ; von Willebrand Factor

Objective To investigate the differential expression profile and bioinformatic analysis of microRNA(miRNA) in human dental pulp cells (DPC) during endothelial differentiation.Methods DPC were cultured in endothelial induction medium ( 50 μg/L vascular endothelial growth factor ,10 μg/L basic fibroblast growth factor and 2% fetal calf serum ) for 7 days.Meanwhile non-induced DPC were used as control.Quantitative real-time PCR ( qRT-PCR ) was applied to detect vascular endothelial marker genes [CD31,von Willebrand factor(vWF) and vascular endothelial-cadherin(VE-cadherin)] and in vitro tube formation on matrigel was used to analyze the angiogenic ability of differentiated cells.And then miRNA expression profiles of DPC were examined using miRNA microarray and then the differentially expressed miRNA were validated by qRT-PCR.Furthermore,bioinformatic analysis was employed to predict the target genes of miRNA and to analyze the possible biological functions and signaling pathways that were involved in DPC after induction.Results The relative mRNA level of CD 31 ,vWF and VE-cadherin in the control group were (3.48 ±0.22) ×10 -4 ,(3.13 ±0.31) ×10 -4 and (39.60 ±2.36) ×10 -4 ,and (19.57 ±2.20) × 10 -4 ,(48.13 ±0.54) ×10 -4 and (228.00 ±8.89) ×10 -4 in the induced group.The expressions of CD31 , vWF and VE-cadherin were increased significantly in endothelial induced DPC compared to the control group (P<0.05).For in vitro tube formation assay,tubular structures were formed on the matrigel by differentiated DPC.A total of 47 miRNA were differentially expressed , in which 15 miRNA were up-regulated and 32 miRNAs down-regulated in differentiated DPC compared with the control.Of these,4 miRNA were confirmed by qRT-PCR.The target genes of differential miRNA were predicted to associate with several biological functions,such as the regulation of transcription ,cell motion,blood vessel morphogenesis ,angiogenesis and cytoskeletal protein ,and signaling pathways including the mitogen-activated protein kinase ( MAPK) and the Wnt signaling pathway.Conclusions The differential miRNA expression identified in this study may be involved in governing DPC endothelial differentiation , thus contributing to the future research on regulatory mechanisms in dental pulp angiogenesis.